1. Field of the Invention
The present invention relates to a mechanical joint, and more particularly to a joint with multi-degree-of-freedom action.
2. Description of Related Art
A multi-degree-of-freedom motion mechanism may be applied to an action mechanism of a camera lens of a robot head, and may be applied to a joint mechanism such as a robot shoulder, elbow, wrist, knee or ankle, and may also be applied to an adapter connected to a searchlight, antenna, radar antenna or hub and used as a joint of a transmission box and a joint of a flying facility.
There are several patent technologies concerning a multi-degree-of-freedom action joint, for example, the joints mechanism disclosed by Taiwan Patent Publishing No. 200626320 uses a convex gear and a concave gear to constitute a spherical gear pair and forms the whole joints mechanism by operating in coordination with three degrees of freedom and cross frame assuming a fixed ratio of speed so as to be able to achieve a spatial power transmission having three degrees of freedom of swaying, oscillation and rotation concurrently. However, a structure of the aforementioned Taiwan patent application is very complex, and difficult to control the actions of the joints by few drive mechanisms. Furthermore, a dexterous split equator joint disclosed by U.S. Pat. No. 6,026,703 uses four semicircular links to drive an arm to move in a hemisphere, and an axis of the arm is passed through the center of sphere. A structure of the aforementioned US patent is also very complex and is not assembled easily, the production cost is high and the arm is not allowed to process a rotation action such that a requirement that a logic operational method concerning clipping and picking up an article through a mechanical arm obtains a unique solution cannot be satisfied and a situation of infinite sets of solutions will be generated to cause the mechanical arm not to complete the article clipping action autonomously.